Dehydrogenation processes for the conversion of saturated organic compounds to compounds having a higher degree of unsaturation are well known. Continued efforts have been made in recent years to improve such processes in order to improve the conversion rate and selectivity to desired products. The present invention describes a continuous process for the oxidative dehydrogenation of saturated hydrocarbons such as ethane to ethylene and acetylene, and propane to propene and propyne. In the present invention, water is a byproduct, and electricity is generated.
U.S. Pat. No. 4,329,208 describes the oxidation of ethylene to ethylene oxide in an electrochemical cell which is similar to the electrochemical cell utilized in the present invention.
U.S. Pat. Nos. 4,327,238, 4,368,346, 4,389,337 and 4,396,537 describe traditional heterogeneous processes (and catalysts) for the oxidative dehydrogenation of ethane to ethylene. In the process described in these patents, cyclic experiments are described wherein air is first passed over the catalysts followed by ethane. Selectivities of up to 98% at 53% conversion are described in the examples. An article by Otsuka et al in Chemistry Letters, (Japan) pages 319-322, 1985, describe the conversion of methane to ethane/ethylene in an electrocatalytic cell using silver and silver/bismuth oxide as the anode materials. In an earlier publication, Bull. Chem. Soc. Jpn., 57, 3286-3289 (1984), the same authors have described steam reforming of hydrocarbons through a wall of stabilized zirconia which acts as a hydrogen separator. The desired product is hydrogen with a minimum of carbon dioxide, carbon monoxide or hydrocarbons.
Michaels and Vayenas, J. Catalysis, 85, 477-487 (1984) have described the vapor phase electrochemical oxidative dehydrogenation of ethyl benzene to styrene on a polycrystalline platinum electrocatalyst in a stabilized zirconia electrochemical reactor. The dehydrogenation rate is reported to be enhanced by moderate current densities.